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Background: Recent detailed analyses of data on dietary sources of energy and nutrients in US children are lacking. The objective of this study was to identify food sources of energy and 28 nutrients for children in the United States. Methods: Analyses of food sources were conducted using a single 24-h recall collected from children 2 to 18 years old (n = 7332) in the 2003–2006 National Health and Nutrition Examination Survey. Sources of nutrients contained in foods were determined using nutrient composition databases. Food grouping included ingredients from disaggregated mixtures. Mean energy and nutrient intakes from the total diet and from each food group were adjusted for the sample design using appropriate weights. Percentages of the total dietary intake that food sources contributed were tabulated by rank order. Results: The two top ranked food/food group sources of energy and nutrients were: energy—milk (7% of energy) and cake/cookies/quick bread/pastry/pie (7%); protein—milk (13.2%) and poultry (12.8%); total carbohydrate—soft drinks/soda (10.5%) and yeast bread/rolls (9.1%); total sugars—soft drinks/soda (19.2%) and yeast breads and rolls (12.7%); added sugars—soft drinks/soda (29.7%) and candy/sugar/sugary foods (18.6%); dietary fiber—fruit (10.4%) and yeast bread/rolls (10.3%); total fat—cheese (9.3%) and crackers/popcorn/pretzels/chips (8.4%); saturated fatty acids—cheese (16.3%) and milk (13.3%); cholesterol—eggs (24.2%) and poultry (13.2%); vitamin D—milk (60.4%) and milk drinks (8.3%); calcium—milk (33.2%) and cheese (19.4%); potassium—milk (18.8%) and fruit juice (8.0%); and sodium—salt (18.5%) and yeast bread and rolls (8.4%). Conclusions: Results suggest that many foods/food groupings consumed by children were energy dense, nutrient poor. Awareness of dietary sources of energy and nutrients can help health professionals design effective strategies to reduce energy consumption and increase the nutrient density of children’s diets.

The US food supply provides an overabundance of energy and nutrients [1]; however, most children do not consume the amounts and types of foods consistent with dietary recommendations [2,3]. Children, especially young children, have high nutrient needs for growth and development, but relatively modest energy requirements, leaving little room for energy-dense, nutrient-poor foods in the diet [4]. Thus, it is important to encourage nutrient dense food choices and diets. Dietary preferences are established early in life [5,6,7]. Establishing a healthful diet in childhood may help reduce the risk of developing diet-related chronic diseases in adulthood [8,9,10].

Critical nutrition concerns for US children include excessive intake of energy which may increase the risk for weight gain and development of obesity. Data from the 2007–2008 National Health and Nutrition Examination Survey (NHANES) showed that among children 2 to 19 years (y), 31.7% were overweight and 16.9% were obese [11]. Overweight/obesity in children has been associated with adverse lipid levels, blood glucose derangements, elevated blood pressure [12,13,14], behavioral and psychosocial problems [15,16], and adult atherosclerosis [17] and obesity [12,13,14,18]. Excess consumption of saturated fatty acids (SFA) has been associated with increased plasma total and low-density lipoprotein cholesterol in childhood [19,20,21], which could increase cardiovascular disease risk; however, recent research has brought this association into question [22,23]. Inadequate consumption of foods rich in dietary fiber, vitamin D, calcium, and potassium [24,25] are major public health concerns. Intake of dietary fiber has been associated with decreased heart disease, obesity, and type 2 diabetes risks [26]. Inadequate intake of nutrients, such as vitamin D and calcium, in combination with a sedentary lifestyle in childhood, can impede the achievement of maximal bone mineral content and density, thereby increasing the diet-related risk of developing osteoporosis later in life [27]. In childhood, overconsumption of sodium, especially with inadequate intake of potassium, has been associated with hypertension [28].

Recent detailed analyses of data on dietary sources of energy and nutrients in US children are lacking. In 1998, Subar et al. [29] reported disaggregated dietary sources of energy and nutrients among US children from the 1989 to 1991 Continuing Survey of Food Intakes by Individuals (CSFII). Recently, using data from the 2003–2004 or 2005–2006 NHANES, dietary sources of total energy and energy from solid fats and added sugars, respectively, were reported [30]. The purpose of this study was to update previous research by examining dietary sources of energy and 28 nutrients using data from a recent nationally representative sample of US children 2 to 18 y. Understanding what children are consuming can help shape appropriate interventions to improve their diet and ultimately their health.

2. Methods2.1. Population and Dietary Intake

The survey design, questionnaires, and examination methodology of NHANES have been described previously [31]. Intake data from children 2 to 18 y (n = 7332) participating in the 2003–2006 NHANES were obtained from in-person 24-h dietary recall interviews using an automated multiple-pass method [32,33]. Descriptions of dietary interview methods have also been described previously [34]. Data judged incomplete or unreliable by the Food Surveys Research Group were excluded from analyses. Since this was a secondary data analysis, the current study was exempted by the Louisiana State University Agricultural Center Institutional Review Board.

2.2. Food Groupings and Composition

The USDA Dietary Sources of Nutrients (DSN) database [35] was used to define food groups. The DSN database was originally developed for use with the CSFII 1994–1996. Therefore, for this research the DSN database was updated for application to recent food consumption surveys. The food grouping and disaggregation rules used to update the DSN database were similar to those methods reported by others who have described dietary sources of nutrients in the American diet [36,37]. The more than 130 DSN food groups were collapsed into 51 categories, an aggregation level consistent with that used by the USDA Food Surveys Research Group when defining food groups [38,39].

If foods were not disaggregated in the DSN database, the Food and Nutrient Database for Dietary Studies (FNDDS) codes were assigned to DSN food groups (FNDDS versions 2.0 [38] and 3.0 [39] were used in 2003–2004 and 2005–2006 NHANES, respectively). The ingredients of disaggregated survey food recipes (coded using the USDA Nutrient Database for Standard Reference [SR] food codes) were linked to the appropriate food composition databases using the SR-Link file of the FNDDS (versions 2.0 [38] and 3.0 [39] link SR releases 18 [40] and 20 [41], respectively). Recipe calculations were performed to determine proportions of the disaggregated survey foods assigned to the 51 DSN food groups.

2.3. Statistical Analyses

Analyses were conducted using SUDAAN 9.0.3 (Research Triangle Institute, Research Triangle Park, NC, USA; 2007). Appropriate weighting factors were used in analyses to adjust for oversampling of selected groups, survey non-response of some individuals, and day of the week the interview was conducted [42]. Mean and standard errors of energy and nutrient intakes from the total diet and from each food group were determined using PROC DESCRIPT of SUDAAN. Using the mean intake data, the average percentage of total dietary intake of energy and nutrients contributed from each food group was calculated and tabulated in ranked order.

The detailed analysis of children’s nutrient intake by Subar et al. [37] used data from the 1989–1991 CSFII that is now more than two decades old. Since then, forces driving trends in children’s food/beverage consumption have included an increased number of meals consumed outside the home [43]; trade liberalization which has increased the number of foods available [44]; changing beverage [45,46], food [47], and snacking preferences [48]; availability of competitive foods in schools [49]; and food product reformulations in response to consumers’ health concerns [50]. More recent data [30] only provided information on total energy, solid fat, and added sugar intake among children. Thus, it was important to provide a more detailed analysis of children’s diet using recent nationally representative data. Faced with a pediatric obesity epidemic, it is important to identify principal sources of energy. This study showed that major sources of energy in children’s diets are not necessarily the same food groups that provide rich sources of nutrients. Of the 10 highest ranked foods/food groups, five groups including milk, yeast bread/rolls, cheese, poultry, and beef accounted for approximately 27% of energy intake; these foods/food groups provided a variety of nutrients, including calcium, vitamin D, and potassium. In their lowest fat form, these foods/food groups are recommended by MyPlate [51]. In contrast the other five food/food groups that were major energy sources (27% combined): cake/cookies/quick bread/pastry/pie, crackers/popcorn/pretzels/chips, soft drinks/soda, fruit drinks/ades, and candy/sugars/sugary foods, contributed mainly fat or added sugars and few other nutrients. That many of the major sources of energy are nutrient-poor foods is consistent with reports that many children do not follow dietary recommendations, and without consuming recommended amounts of nutrient-dense foods, such as whole grains, fruit, vegetables, low-fat milk, and lean meat, diets can be nutritionally inadequate [3].

Soft drinks/soda and fruit drinks/ades contributed 5.5% and 3.5% of energy, respectively; if these two sweetened beverage categories were combined, they provided a higher percentage (9%) than any other source of energy in the diet. Subar et al. [29] also showed that soft drinks and soda were major contributors of energy to the diets of children (4.3%); however, in that study, fruit drinks provided only 2.2% of energy intake. Reedy, et al. [30] also reported soft drinks and soda as a major source of energy. From 1977 to 2006, children’s beverage consumption patterns changed and intake of sweetened beverages increased from 87 to 154 kcals [45].

Subar et al. [29] reported that the five highest ranked energy sources were milk (11.7%), yeast bread (9.3%), cakes/cookies/quick breads/donuts (6.2%), beef (5.7%), RTEC (4.5%), and soft drinks/soda (4.3%). A comparison of that study and ours suggests a temporal shift in sources of energy occurred. Since our study combined crackers/pretzels with popcorn/chips, and candy with sugars/sugary foods, the ranking of the combined groups was higher than each of the individual groups studied in Subar’s study.

Data from children in the 2005–2006 NHANES [30] showed the five highest ranked sources of energy were grain desserts (e.g., cakes) (6.8% of total energy consumed), pizza (6.7%), soda (5.8%), yeast breads (5.6%), and chicken (5.6%). In that study, mixtures were not disaggregated. Grain desserts and soda were identified in that study and ours as major contributors of energy to the diets of children. The study using 2005–2006 NHANES data separated milk by fat level, and therefore milk was not identified as a major source of energy in children’s diets; however, if whole and reduced-fat milk were combined they contributed the highest percentage of energy to the diet.

The same five highest sources of protein were identified by Subar et al. [29], albeit with a different rank order. Cheese and milk were the two highest ranked sources of SFA, followed by frankfurters/sausages/luncheon meats. The contribution of SFA in the diet by milk, beef and frankfurters/sausages/luncheon meats shown in our study was lower and cheese and crackers/popcorn/pretzels/chips was higher when compared with the 1989–1992 CSFII data [29]. Current dietary recommendations are to replace SFA with mono-unsaturated fatty acids (MUFA) and poly-unsaturated fatty acids (PUFA) [25] since the latter are associated with decreased cardiovascular risk [52]. Our study showed that of the five highest ranked sources of MUFA (cake/cookies/quick bread/pastry/pie, frankfurters/sausages/luncheon meats, other fats/oils, beef, and crackers/popcorn/pretzels/chips) (Supplemental Tables); beef was the only nutrient dense food. Of the five highest ranked sources of PUFA, poultry was the only nutrient-dense food. Intake of nutrient dense sources of oils, such as nuts, should be encouraged (Supplemental Tables).

The 2010 Dietary Guidelines for Americans recognized the low intakes of dietary fiber, calcium, vitamin D and potassium were of public health concern [25]. Ideally, diets or food patterns containing adequate amounts of these nutrients should be recommended so that intake of nutrient-dense foods can be consumed without unduly increasing energy intake. In children, dietary fiber intake is inversely associated with serum cholesterol levels [53] and constipation [54], a major cause of morbidity in children [55]. Dietary fiber intake by children is approximately half of what is recommended [56]. Fruit was the highest ranked source; however, most children do not consume the recommended amount of fruit [3]. Fruit, yeast bread/rolls, crackers/popcorn/pretzels/chips, potatoes, RTEC, biscuits/corn bread/pancakes/tortillas, legumes, and cake/cookies/quick bread/pastry/pie provided a cumulative 58.5% of fiber intake. Of these foods/food groups, fruit, yeast bread/rolls, potatoes, RTEC, and legumes provide other nutrients while most of the other food/food groups do not. Cake/cookies/quick bread/pastry/pie provided both fat and added sugars and were poor sources of most other nutrients. Because vegetables were split into many different categories, vegetables, other than potatoes, each contributed 4% or less of dietary fiber; however, when categories contributing at least 1% of fiber (e.g., tomatoes and tomato/vegetable juice, “other” vegetables, corn/peas/lima beans; carrots/sweet potatoes/winter squash; broccoli/spinach/greens) were combined, they would be the highest ranked source, providing 10.7% of fiber.

The nutrient contribution of milk and dairy products play an important role in helping American children and adolescents meet recommendations for short-fall nutrients [24] and nutrients of public health concern [25]. In our study, milk was an important source of calcium, potassium, vitamin D, and provided many other nutrients, including vitamin A, thiamin, riboflavin, vitamins B6 and B12, phosphorus, magnesium, and zinc (Supplemental Tables). Subar et al. [29] found that in 1989–1991, milk (including milk drinks) and cheese provided 51.5% and 14.3% of children’s calcium intake. Sources of potassium were not reported in that study, and vitamin D food composition data were not updated or complete when that study was conducted. In our study, milk and milk drinks provided a lower percentage (38.2%), while cheese (19.4%) and other sources such as calcium-fortified fruit juice (3.2%) provided higher percentages of calcium intake than previously reported [29]. A comparison of energy sources shows milk and milk drinks contributed a lower percentage of energy in 2003–2006 than in 1989–1991, while energy contributed from less nutrient-dense foods and beverages increased. This observation is consistent with other reports [57,58,59]. Low-fat and reduced-fat milk are recommended for children after the age of 2 years.

This study has several limitations. Food grouping can have a major influence on the ranked order of dietary sources; thus, caution is advised when comparing these data to previous reports [29,30] if there were differences in the level of aggregation (i.e., the number of food groups) or disaggregation procedures used to include ingredients in food groups. Study outcomes are based on self-reported data that tend to underestimate energy intake [60]. A parent/guardian of children 2–11 y who was a proxy or assistant during the 24-h recall interview can often accurately report what the child consumed at home [61] but may not know what the child consumed outside the home [62]. A single day’s intake is not representative of an individual’s usual intake. However, the mean of the intake distribution drawn from a large, representative sample of a group is not affected by day-to-day variation [63], and since the contribution of food sources is based on mean intake data from NHANES, the use of a single 24-h recall was appropriate [64]. In general, because the food grouping in the USDA DSN database does not include ingredients of manufactured foods, disaggregated foods represent mixtures that are prepared from recipes. The USDA reduces the sodium content of mixtures if the respondent never, rarely, or occasionally uses salt in cooking, and the food was prepared at home; therefore, a large portion of the salt was added to recipes for foods prepared by restaurants, schools, and other establishments (data not shown). Finally, the updated vitamin D database that USDA recently released was appropriate for use with the 2005–2006 NHANES dietary intake data, and because vitamin D intake from foods consumed in 2003–2004 was determined using the updated food composition data, the 2003–2004 intake data may not have been representative of that time period. Any variation in food composition data affects the reliability of dietary intake estimation. It should also be noted that the major sources of vitamin D are fortified foods; changes in vitamin D fortification are regulated by a food additive rule [65]. A petition to add vitamin D to calcium-supplemented juices and fruit drinks was approved by the Food and Drug Administration and implemented in 2004 [66]. However, this change was effective only in the 2005–2006 NHANES, since the new calcium- and vitamin D-supplemented foods were not reported in the 2003–2004 NHANES.

5. Conclusions

This study showed that children consumed a large proportion of total energy from energy-dense, low-nutrient food groups (e.g., cake/cookies/quick bread/pastry/pie and soft drinks/soda) and identified principal sources of energy that were also major sources of nutrients (e.g., milk and milk drinks, poultry, and beef). Awareness of food and beverage sources of energy and nutrients can help health professionals design and promote effective strategies to reduce energy consumption and increase the nutrient density of the diet.

Acknowledgments

This work is a publication of the United States Department of Agriculture (USDA/ARS) Children’s Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine, and Houston, Texas. The contents of this publication do not necessarily reflect the views or policies of the USDA, nor does mention of trade names, commercial products, or organizations imply endorsement from the U.S. government. This research project is supported by the USDA—Agricultural Research Service through specific cooperative agreement 58-6250-6-003, USDA Hatch Project LAB 93951, and the National Dairy Council administered by the Dairy Research Institute. None of the funding agencies contributed to the design or conduct of the study; the collection, management, analysis, or interpretation of the data; or the preparation, review, or approval of the manuscript. TAN and CO’N were independent of the commercial funding source and had full access to the data.

There are no competing interests, other than the funding sources identified above.

Authors’ Contributions

DRK conducted the statistical analysis with VLF; VLF, CO’N, and TAN interpreted the data; CO’N was the principal author; DRK, VLF, and TAN worked to edit and revise the manuscript. All authors contributed equally to this work.

Supplementary FilesSupplementary File 1

Supplemental Tables (PDF, 223 KB)

References1.United States Department of Agriculture Economic Research ServiceNutrient AvailabilityAvailable online:http://www.ers.usda.gov/Data/FoodConsumption/NutrientAvailIndex.htm(accessed on 5 January 2011)2.Usual Dietary Intakes: Food Intakes, US Population, 2001–2004. Risk Factor Monitoring and Methods Branch Web siteAvailable online:http://riskfactor.cancer.gov/diet/usualintakes/pop/(accessed on 24 June 2010)3.Krebs-SmithS.M.GuentherP.M.SubarA.F.KirkpatrickS.I.DoddK.W.Americans do not meet federal dietary recommendationsJ. Nutr.20101401832183810.3945/jn.110.1248264.FoxM.K.CondonE.BriefelR.R.ReidyK.C.DemingD.M.Food consumption patterns of young preschoolers: Are they starting off on the right path?J. Am. Diet. Assoc.2010110S52S595.BirchL.L.SavageJ.S.VenturaA.Influences on the development of children’s eating behaviors: From infancy to adolescenceCan. J. Diet. Pract. Res.200768S1S566.BirchL.L.FisherJ.Development of eating behaviors among children and adolescentsPediatrics19981015395497.BirchL.L.JohnsonS.L.FisherJ.Children’s eating: The development of food-acceptance patternsYoung Child.19955071788.Van der PolsJ.C.GunnellD.WilliamsG.M.HollyJ.M.BainC.MartinR.M.Childhood dairy and calcium intake and cardiovascular mortality in adulthood: 65-year follow-up of the Boyd Orr cohortHeart2009951600160610.1136/hrt.2009.1687169.MaynardM.GunnellD.EmmettP.FrankelS.Davey SmithG.Fruit, vegetables, and antioxidants in childhood and risk of adult cancer: The Boyd Orr cohortJ. Epidemiol. Community Health20035721822510.1136/jech.57.3.21810.FrankelS.GunnellD.J.PetersT.J.MaynardM.Davey SmithG.Childhood energy intake and adult mortality from cancer: The Boyd Orr Cohort StudyBMJ199831649950410.1136/bmj.316.7130.49911.OgdenC.L.CarrollM.D.CurtinL.R.LambM.M.FlegalK.M.Prevalence of high body mass index in US children and adolescents, 2007–2008JAMA201030324224910.1001/jama.2009.201212.MustA.StraussR.S.Risks and consequences of childhood and adolescent obesityInt. J. Obes. Relat. Metab. Disord.199923S2S1110.1038/sj.ijo.080085213.ReillyJ.J.MethvenE.McDowellZ.C.HackingB.AlexanderD.StewartL.KelnarC.J.Health consequences of obesityArch. Dis. Child.20038874875210.1136/adc.88.9.74814.FreedmanD.S.MeiZ.SrinivasanS.R.BerensonG.S.DietzW.H.Cardiovascular risk factors and excess adiposity among overweight children and adolescents: The Bogalusa Heart StudyJ. Pediatr.2007150121710.1016/j.jpeds.2006.08.04215.Young-HymanD.Tanofsky-KraffM.YanovskiS.Z.KeilM.CohenM.L.PeyrotM.YanovskiJ.A.Psychological status and weight-related distress in overweight or at-risk-for-overweight childrenObesity2006142249225810.1038/oby.2006.26416.Hayden-WadeH.A.SteinR.I.GhaderiA.SaelensB.E.ZabinskiM.F.WilfleyD.E. Prevalence, characteristics, and correlates of teasing experiences among overweight children vs. non-overweight peersObes. Res.2005131381139210.1038/oby.2005.16717.BerensonG.S.SrinivasanS.R.BaoW.NewmanW.P.IIITracyR.E.WattigneyW.A.Association between multiple cardiovascular risk factors and atherosclerosis in children and young adultsN. Engl. J. Med.19983381650165610.1056/NEJM19980604338230218.PowerC.LakeJ.K.ColeT.J.Measurement and long term health risks of child and adolescent fatnessInt. J. Obes. Relat. Metab. Disord.19972150752619.StangJ.BayerlC.T.Position of the American Dietetic Association: Child and adolescent nutrition assistance programsJ. Am. Diet. Assoc.201011079179910.1016/j.jada.2010.02.02520.NicklasT.A.DwyerJ.FeldmanH.A.LuepkerR.V.KelderS.H.NaderP.R.Serum cholesterol levels in children are associated with dietary fat and fatty acid intakeJ. Am. Diet. Assoc.200210251151710.1016/S0002-8223(02)90117-321.LawM.Dietary fat and adult diseases and the implications for childhood nutrition: An epidemiological approachAm. J. Clin. Nutr.2000721291S1296S22.FeinmanR.D.Saturated fat and health: Recent advances in researchLipids20104589189210.1007/s11745-010-3446-823.Siri-TarinoP.W.SunQ.HuF.B.KraussR.M.Meta-analysis of prospective cohort studies evaluating the association of saturated fat with cardiovascular diseaseAm. J. Clin. Nutr.20109153554610.3945/ajcn.2009.2772524.Dietary Guidelines for American, 2005: Adequate Nutrients Within Calorie NeedsAvailable online:http://www.health.gov/dietaryguidelines/dga2005/document/html/chapter2.htm(accessed on 24 June 2010)25.Dietary Guidelines for Americans; Technical Report2010Available online:http://www.cnpp.usda.gov/DGAs2010-PolicyDocument.htm(accessed on 20 December 2010)26.A Report of the Panel on Macronutrients, Subcommittees on Upper Reference Levels of Nutrients and Interpretation and Uses of Dietary Reference Intakes, and the Standing Committee on the Scientific Evaluation of Dietary Reference Intakes. Dietary Reference Intakes for Energy, Carbohydrate, Fiber, Fat, Fatty Acids, Cholesterol, Protein, and Amino Acids (Macronutrients) 2005Available online:http://www.nap.edu/catalog.php?record_id=10490(accessed on 24 June 2010)27.MoshfeghA.GoldmanJ.AhujaJ.RhodesD.LaCombR.What We Eat in America, NHANES 2005–2006: Usual Nutrient Intakes from Food and Water Compared to 1997 Dietary Reference Intakes for Vitamin D, Calcium, Phosphorus, and Magnesium; Technical Report for U.S. Department of AgricultureAgricultural Research ServiceBeltsville, MD, USA2009Available online:Available online: http://www.ars.usda.gov/SP2UserFiles/Place/12355000/pdf/0506/usual_nutrient _intake_vitD_ca_phos_mg_2005-06.pdf(accessed on 5 January 2011)28.GeleijnseJ.M.GrobbeeD.E.HofmanA.Sodium and potassium intake and blood pressure change in childhoodBMJ199030089990210.1136/bmj.300.6729.89929.SubarA.F.Krebs-SmithS.M.CookA.KahleL.L.Dietary sources of nutrients among US children, 1989–1991Pediatrics199810291392310.1542/peds.102.4.91330.ReedyJ.Krebs-SmithS.M.Dietary sources of energy, solid fats, and added sugars among children and adolescents in the United StatesJ. Am. Diet. Assoc.20101101477148410.1016/j.jada.2010.07.01031.National Center for Health Statistics, 2009. National Health and Nutrition Examination Survey Web siteAvailable online:http://www.cdc.gov/nchs/nhanes.htm(accessed on 5 January 2011)32.MoshfeghA.J.RhodesD.G.BaerD.J.MurayiT.ClemensJ.C.RumplerW.V.PaulD.R.SebastianR.S.KuczynskiK.J.IngwersenL.A.The US Department of Agriculture Automated Multiple-Pass Method reduces bias in the collection of energy intakesAm. J. Clin. Nutr.20088832433233.BlantonC.A.MoshfeghA.J.BaerD.J.KretschM.J.The USDA Automated Multiple-Pass Method accurately estimates group total energy and nutrient intakeJ. Nutr.20061362594259934.National Health and Nutrition Examination Survey (NHANES)MEC In-Person Dietary Interviewers Procedures Manual; Technical ReportJanuary2006Available online:http://www.cdc.gov/nchs/data/nhanes/nhanes_05_06/DIETARY_MEC.pdf(accessed on 27 March 2010)35.U.S. Department of Agriculture Agricultural Research ServiceProducts and ServicesAvailable online:http://www.ars.usda.gov/Services/docs.htm?docid=8498(accessed on 24June 2010)36.CottonP.A.SubarA.F.FridayJ.E.CookA.Dietary sources of nutrients among US adults, 1994 to 1996J. Am. Diet. Assoc.200410492193010.1016/j.jada.2004.03.01937.SubarA.F.Krebs-SmithS.M.CookA.KahleL.L.Dietary sources of nutrients among US adults, 1989 to 1991J. Am. Diet. Assoc.19989853754710.1016/S0002-8223(98)00122-938.USDA Food and Nutrient Database for Dietary Studies 2.0; U.S. Department of Agriculture Agricultural Research Service Web site2006Available online:http://www.ars.usda.gov/Services/docs.htm?docid=12083(accessed on 5 January 2011)39.The USDA Food and Nutrient Database for Dietary Studies, 3.0; U.S. Department of Agriculture Agricultural Research Service Web site2008Available online:http://www.ars.usda.gov/Services/docs.htm?docid=17031(accessed on 5 January 2011)40.U.S. Department of Agriculture, Agricultural Research ServiceUSDA National Nutrient Database for Standard Reference, Release 18; Technical Report2005Available online:http://www.ars.usda.gov/Services/docs.htm?docid=13747(accessed on 4 January 2011)41.U.S. Department of Agriculture, Agricultural Research ServiceUSDA National Nutrient Database for Standard Reference, Release 20; Technical report2007Available online:http://www.ars.usda.gov/Services/docs.htm?docid=17476(accessed on 4 January 2011)42.Centers for Disease Control and Prevention; National Center for Health Statistics; National Health and Nutrition Examination Survey. Analytic Guidelines. Centers for Disease Control and Prevention Web siteAvailable online:http://www.cdc.gov/nchs/nhanes/nhanes2003-2004/analytical_guidelines.htm(accessed on 24 June 2010)43.MancinoM.ToddJ.E.GuthrieJ.LinB.-H.How Food away from Home Affects Children’s Diet Quality; Economic Research Report No. ERR-104October2010Available online:http://www.ers.usda.gov/Publications/err104/err104.pdf(accessed on 5 January 2010)44.KearneyJ.Food consumption trends and driversPhilos. Trans. R. Soc. Lond B Biol. Sci.2010365279380710.1098/rstb.2010.014945.PopkinB.M.Patterns of beverage use across the lifecyclePhysiol. Behav.20101004910.1016/j.physbeh.2009.12.02246.SebastianR.ClevelandL.E.GoldmanJ.D.MoshfeghA.J.Trends in the food intakes of children 1977–2002Consum. Interests Annu.20065243343447.DavisC.BlayneyD.P.DongD.StefanovaS.JohnsonA.Long-Term Growth in U.S. Cheese Consumption May Slow; Outlook Report No. LDPM-193-01August2010Available online:http://www.ers.usda.gov/Publications/LDP/2010/07Jul/LDPM19301(accessed on 6 January 2011)48.United States Department of Agriculture Agricultural Research Service. Beltsville Human Nutrition Research Center Food Surveys Research GroupSnacking Patterns of US Adolescents: What We Eat in America, NHANES 2005–2006; Technical Report2010Available online:http://www.ars.usda.gov/SP2UserFiles/Place/12355000/pdf/DBrief/snacking_0506.pdf(accessed on 6 January 2011)49.KakaralaM.KeastD.R.HoerrS.Schoolchildren’s consumption of competitive foods and beverages, excluding à la carteJ. Sch. Health20108042943510.1111/j.1746-1561.2010.00524.x50.ZinkD.L.The impact of consumer demands and trends on food processingEmerg. Infect. Dis.1997346746910.3201/eid0304.97040851.United States Department of Agriculture MyPlate Web siteAvailable online:http://www.choosemyplate.gov(accessed on 20 December 2011)52.SmitL.A.MozaffarianD.WillettW.Review of fat and fatty acid requirements and criteria for developing dietary guidelinesAnn. Nutr. Metab.200955445510.1159/00022899553.WilliamsC.L.StrobinoB.A.Childhood diet, overweight, and CVD risk factors: The Healthy Start projectPrev. Cardiol.200811112010.1111/j.1520-037X.2007.06677.x54.LeeW.T.IpK.S.ChanJ.S.LuiN.W.YoungB.W.Increased prevalence of constipation in pre-school children is attributable to under-consumption of plant foods: A community-based studyJ. Paediatr. Child. Health20084417017510.1111/j.1440-1754.2007.01212.x55.Loening-BauckeV.Functional constipationSemin. Pediatr. Surg.19954263456.Nutrient Intakes: Mean Amounts Consumed per Individual, One Day, 2003–2004; Technical Report14December2007Available online:http://www.ars.usda.gov/SP2UserFiles/Place/12355000/pdf/0304/Table_1_NIF.pdf(accessed on 16 July 2008)57.United States Department of Agriculture Agricultural Research Service2010 Fluid Milk Consumption in the United States, What We Eat in America, NHANES 2005–2006; Technical ReportAvailable online:http://www.ars.usda.gov/SP2UserFiles/Place/12355000/pdf/DBrief/fluid_milk_0506.pdf(accessed on 6 January 2011)58.GordonA.R.CrepinsekM.K.BriefelR.R.ClarkM.A.FoxM.K.The third School Nutrition Dietary Assessment Study: Summary and implicationsJ. Am. Diet. Assoc.2009109S129S13510.1016/j.jada.2008.10.06659.BriefelR.R.WilsonA.GleasonP.M.Consumption of low-nutrient, energy-dense foods and beverages at school, home, and other locations among school lunch participants and nonparticipantsJ. Am. Diet. Assoc.2009109S79S9010.1016/j.jada.2008.10.06460.BinghamS.A.GillC.WelchA.DayK.CassidyA.KhawK.T.SneydM.J.KeyT.J.RoeL.DayN.E.Comparison of dietary assessment methods in nutritional epidemiology: Weighed records v. 24 h recalls, food-frequency questionnaires and estimated-diet recordsBr. J. Nutr.19947261964310.1079/BJN1994006461.BaschC.E.SheaS.ArlissR.ContentoI.R.RipsJ.GutinB.IrigoyenM.ZybertP.Validation of mothers’ reports of dietary intake by four to seven year-old childrenAm. J. Public Health1990801314131710.2105/AJPH.80.11.131462.BaranowskiT.SpragueD.BaranowskiJ.H.HarrisonJ.A.Accuracy of maternal dietary recall for preschool childrenJ. Am. Diet. Assoc.19919166967463.GuentherP.M.KottP.S.CarriquiryA.L.Development of an approach for estimating usual nutrient intake distributions at the population levelJ. Nutr.19971271106111264.ThompsonF.E.ByersT.Dietary assessment resource manualJ. Nutr.19941242245S2317S65.Food Additives Permitted for Direct Addition to Food for Human Consumption; Vitamin D2Available online:http://www.federalregister.gov/articles/2009/03/16/E9-5549/food-additives-permitted-for-direct-addition-to-food-for-human-consumption-vitamin-d2(accessed on 6 January 2011)66.MooreC.E.MurphyM.M.KeastD.R.HolickM.Vitamin D intake in the United StatesJ. Am. Diet. Assoc.200410498098310.1016/j.jada.2004.03.028